Councillors are to spend the pounds so the public can spend a penny at a new toilet near Pimlico Station.
Westminster Council has approved plans for a new convenience outside the tube station, in Lupus Street, Pimlico.
Councillors decided to take action after they found there was a growing problem with people urinating in streets and alleyways surrounding the station.
The idea of installing a public toilet was floated with residents in debates at two area forums last year and they supported the scheme. There will be a self-cleaning toilet cubilce with two external urinals, to cope with an overflow of traffic.
The cost of the unit will be £80,000 and it will cost around £14,000 a year to maintain and operate it, although these costs will reduce over time.
Cabinet member for neighbourhoods councillor Audrey Lewis said she supported the scheme. "Tachbrook ward councillors have decided to spend money from their ward budget on installing a toilet close to Pimlico Station which, hopefully, should put an end to people urinating in the street there," she said.
After the council gives the scheme the green light this week, it will open throw the work open to potential contractors in a tender process.
Another month will be needed for Thames Water to inspect the site and give the council an estimate on water costs and a further two months to put in sewage connections.
But by far the slowest part of the process is connecting the toilet up to mains electricity which is expected to take up to six months.
The council hopes to have the toilet up and flushing by July, in time for the summer drinking season.
For some, the lavatory cannot come soon enough.
"It's a brilliant idea," said Irene Dimmock from nearby Churchill Gardens Estate, in Churchill Gardens Road. "I have only seen one or two urinating in the street myself but I know it is a problem around here."